Per-aneurysm Basis Research Articles

A deep-learning model for intracranial aneurysm detection on CT angiography images in China: a stepwise, multicentre, early-stage clinical validation study

Artificial intelligence (AI) models in real-world implementation are scarce. Our study aimed to develop a CT angiography (CTA)-based AI model for intracranial aneurysm detection, assess how it helps clinicians improve diagnostic performance, and validate its application in real-world clinical implementation. We developed a deep-learning model using 16 546 head and neck CTA examination images from 14 517 patients at eight Chinese hospitals. Using an adapted, stepwise implementation and evaluation, 120 certified clinicians from 15 geographically different hospitals were recruited. Initially, the AI model was externally validated with images of 900 digital subtraction angiography-verified CTA cases (examinations) and compared with the performance of 24 clinicians who each viewed 300 of these cases (stage 1). Next, as a further external validation a multi-reader multi-case study enrolled 48 clinicians to individually review 298 digital subtraction angiography-verified CTA cases (stage 2). The clinicians reviewed each CTA examination twice (ie, with and without the AI model), separated by a 4-week washout period. Then, a randomised open-label comparison study enrolled 48 clinicians to assess the acceptance and performance of this AI model (stage 3). Finally, the model was prospectively deployed and validated in 1562 real-world clinical CTA cases. The AI model in the internal dataset achieved a patient-level diagnostic sensitivity of 0·957 (95% CI 0·939-0·971) and a higher patient-level diagnostic sensitivity than clinicians (0·943 [0·921-0·961] vs 0·658 [0·644-0·672]; p<0·0001) in the external dataset. In the multi-reader multi-case study, the AI-assisted strategy improved clinicians' diagnostic performance both on a per-patient basis (the area under the receiver operating characteristic curves [AUCs]; 0·795 [0·761-0·830] without AI vs 0·878 [0·850-0·906] with AI; p<0·0001) and a per-aneurysm basis (the area under the weighted alternative free-response receiver operating characteristic curves; 0·765 [0·732-0·799] vs 0·865 [0·839-0·891]; p<0·0001). Reading time decreased with the aid of the AI model (87·5 s vs 82·7 s, p<0·0001). In the randomised open-label comparison study, clinicians in the AI-assisted group had a high acceptance of the AI model (92·6% adoption rate), and a higher AUC when compared with the control group (0·858 [95% CI 0·850-0·866] vs 0·789 [0·780-0·799]; p<0·0001). In the prospective study, the AI model had a 0·51% (8/1570) error rate due to poor-quality CTA images and recognition failure. The model had a high negative predictive value of 0·998 (0·994-1·000) and significantly improved the diagnostic performance of clinicians; AUC improved from 0·787 (95% CI 0·766-0·808) to 0·909 (0·894-0·923; p<0·0001) and patient-level sensitivity improved from 0·590 (0·511-0·666) to 0·825 (0·759-0·880; p<0·0001). This AI model demonstrated strong clinical potential for intracranial aneurysm detection with improved clinician diagnostic performance, high acceptance, and practical implementation in real-world clinical cases. National Natural Science Foundation of China. For the Chinese translation of the abstract see Supplementary Materials section.

Diagnostic Validity of 3D-Computed Tomographic Angiography in Spontaneous Subarachnoid Haemorrhage

Background: Diagnostic validity of different tests for the detection of spontaneous subarachnoid haemorrhage is an important issue.&#x0D; Objectives: The purpose of the present study was to validate 3D-Computed tomographic angiography in spontaneous subarachnoid haemorrhage.&#x0D; Methodology: This cross-sectional study was carried out in the Department of Neurosurgery and Cath Lab of DMCH in collaboration with private diagnostic centre from September 2013 to February 2015 for a period of six (06) months. Adult patients diagnosed as a case of spontaneous SAH based on clinical features and confirmed by plain CT evidence of subarachnoid blood were included as study population. Patients having current history of trauma, poor clinical grade and agitated patient, patient with renal insufficiency, known allergy to iodinated contrast agent and patients who were not willing participate in the study were excluded from this study. Then both CT angiography and DSA were performed to detect cause of bleeding and to make a treatment planning. In this study DSA was considered as reference standard for evaluation of CTA. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of CTA were calculated per patient basis and per aneurysmal basis.&#x0D; Result: A total number of 37 patients presented with spontaneous subarachnoid haemorrhage were recruited for this study. The mean age of patients was 58.53±7.54 years. Sensitivity and specificity in depicting intracranial aneurysms were, 93.75% and 100% respectively on a per-patient basis. Positive predictive value and negative predictive value of CTA are 100% and 71.43% respectively. CTA had shown 94.59% accuracy in detection of intracranial aneurysm. Sensitivity and specificity in depicting intracranial aneurysms were 94.74% and 100% respectively on a per-aneurysm basis. Positive predictive value and negative predictive value of CTA are 100% and 71.43% respectively. CTA had shown 95.35% accuracy in detection of intracranial aneurysm.&#x0D; Conclusion: In conclusion CTA has high detection capacity of aneurysm among spontaneous subarachnoid haemorrhage patients.&#x0D; Journal of National Institute of Neurosciences Bangladesh, 2019;5(1): 47-52

Use of the stereoscopic virtual reality display system for the detection and characterization of intracranial aneurysms: A Icomparison with conventional computed tomography workstation and 3D rotational angiography

ObjectiveThis study aimed to compare the diagnostic performance of the stereoscopic virtual reality display system with the conventional computed tomography (CT) workstation and three-dimensional rotational angiography (3DRA) for intracranial aneurysm detection and characterization, with a focus on small aneurysms and those near the bone. Patients and methodsFirst, 42 patients with suspected intracranial aneurysms underwent both 256-row CT angiography (CTA) and 3DRA. Volume rendering (VR) images were captured using the conventional CT workstation. Next, VR images were transferred to the stereoscopic virtual reality display system. Two radiologists independently assessed the results that were obtained using the conventional CT workstation and stereoscopic virtual reality display system. The 3DRA results were considered as the ultimate reference standard. ResultsBased on 3DRA images, 38 aneurysms were confirmed in 42 patients. Two cases were misdiagnosed and 1 was missed when the traditional CT workstation was used. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the conventional CT workstation were 94.7%, 85.7%, 97.3%, 75%, and99.3%, respectively, on a per-aneurysm basis. The stereoscopic virtual reality display system missed a case. The sensitivity, specificity, PPV, NPV, and accuracy of the stereoscopic virtual reality display system were 100%, 85.7%, 97.4%, 100%, and 97.8%, respectively. No difference was observed in the accuracy of the traditional CT workstation, stereoscopic virtual reality display system, and 3DRA in detecting aneurysms. ConclusionThe stereoscopic virtual reality display system has some advantages in detecting small aneurysms and those near the bone. The virtual reality stereoscopic vision obtained through the system was found as a useful tool in intracranial aneurysm diagnosis and pre-operative 3D imaging.

Small Intracranial Aneurysms: Diagnostic Accuracy of CT Angiography.

Purpose To assess the accuracy of computed tomographic (CT) angiography for diagnosis of cerebral aneurysms 5 mm or smaller, with digital subtraction angiography (DSA) as the reference standard, in a large patient cohort Materials and Methods This retrospective study was approved by the local institutional review board with a waiver of written informed consent. A total of 1366 patients who underwent cerebral CT angiography followed by DSA were included. The performance of CT angiography for depiction of aneurysms was evaluated by two readers on a per-patient and per-aneurysm basis and based on size of aneurysm, location, and status of rupture. The performance of CT angiography for diagnosis of aneurysms of different size, location, and rupture status was compared by using χ2 test. κ statistic was used to assess interreader agreement for diagnosis of aneurysms. Results Of 1366 patients, 579 patients had 711 small aneurysms at DSA. By using DSA as the reference standard, the respective sensitivity, specificity, and accuracy of CT angiography for readers 1 and 2 for detection of small aneurysms on a per-patient basis were 97.1% (562 of 579) and 97.4% (564 of 579), 98.5% (451 of 458) and 99.1% (454 of 458), and 97.7% (1013 of 1037) and 98.2% (1018 of 1037) and those on a per-aneurysm basis were 95.2% (677 of 711) and 95.4% (678 of 711), 96.6% (451 of 467) and 97.0% (454 of 468), and 95.8% (1128 of 1178) and 96.0% (1132 of 1179). The sensitivities of CT angiography were lower for detection of aneurysms smaller than 3 mm and unruptured compared with aneurysms that were 3-5 mm and ruptured (P < .001). No difference existed for the sensitivities of CT angiography for diagnosis of aneurysms in the anterior versus posterior circulation (P > .0167). Excellent or good interreader agreement was found for detection of intracranial aneurysms on a per-patient (κ = 0.982) and per-aneurysm (κ = 0.748) basis. Conclusion This large cohort study demonstrated that CT angiography had high accuracy for detection of small cerebral aneurysms, including those smaller than 3 mm. © RSNA, 2017 Online supplemental material is available for this article.

Cerebral CTA with Low Tube Voltage and Low Contrast Material Volume for Detection of Intracranial Aneurysms.

Multidetector row CTA has become the primary imaging technique for detecting intracranial aneurysms. Technical progress enables the use of cerebral CTA with lower radiation doses and contrast media. We evaluated the diagnostic accuracy of 80-kV(peak) cerebral CTA with 30 mL of contrast agent for detecting intracranial aneurysms. Two hundred four patients were randomly divided into 2 groups. Patients in group A (n = 102) underwent 80-kVp CTA with 30 mL of contrast agent, while patients in group B (n = 102) underwent conventional CTA (120 kVp, 60 mL of contrast agent). All patients underwent DSA. Image quality, diagnostic accuracy, and radiation dose between the 2 groups were compared. Diagnostic image quality was obtained in 100 and 99 patients in groups A and B, respectively (P = .65). With DSA as reference standard, diagnostic accuracy on a per-aneurysm basis was 89.9% for group A and 93.9% for group B. For evaluating smaller aneurysms (<3 mm), the diagnostic accuracy of groups A and B was 86.3% and 90.8%, respectively. There was no difference in diagnostic accuracy between each CTA group and DSA (all, P > .05) or between the 2 CTA groups (all, P > .05). The effective dose in group A was reduced by 72.7% compared with group B. In detecting intracranial aneurysms with substantial radiation dose and contrast agent reduction, 80-kVp/30-mL contrast CTA provides the same diagnostic accuracy as conventional CTA.

Diagnosis and Treatment of Intracranial Aneurysms with 320-Detector Row Volumetric Computed Tomography Angiography

The objective of the study was to determine the clinical utility of 320-detector row volume-computed tomographic angiography (VCTA) in the management of intracranial aneurysms. Between February 2011 and May 2015, 550 patients successfully underwent 320-detector row VCTA for suspected intracranial aneurysms. Three-dimensional (3D) digital subtraction angiography (DSA) was used as the ultimate reference standard, and the sensitivity, specificity, and accuracy of both nonsubtracted and subtracted VCTA in identifying aneurysms were analyzed. Nonsubtracted VCTA identified 417 aneurysms (2 false-positive readings, 12 false-negative readings). The diagnostic sensitivity, specificity, and accuracy of non-subtracted VCTA, on a per-aneurysm basis, were 97.2%, 99.0%, and 97.6%, respectively. Subtracted VCTA identified 426 aneurysms (2 false-positive readings, 3 false-negative readings). The sensitivity, specificity, and accuracy of subtracted VCTA, on a per-aneurysm basis, were 99.3%, 99.0%, and 99.2%, respectively. No differences in diagnostic accuracy were found between subtracted VCTA and 3D DSA. Nonsubtracted VCTA, however, was observed to be significantly less sensitive than 3D DSA and subtracted VCTA. Twenty-six aneurysm cases were referred for surgical treatment based on VCTA imaging. All aneurysms were deemed completely occluded during surgical clipping. On the basis of VCTA imaging, 299 aneurysms were found suitable for endovascular coiling, of which 293 aneurysms (98%) were treated successfully. The 320-detector row subtracted VCTA technique is an effective, first-line diagnostic imaging modality for surgical and endovascular treatment of aneurysms. The nonsubtracted VCTA was less accurate than the subtracted VCTA, especially for intracranial aneurysms adjoining bone tissue.

Subtraction CT angiography for the detection of intracranial aneurysms: A meta-analysis.

The aim of this meta-analysis was to investigate the accuracy of subtraction computed tomography angiography (CTA) for diagnosing intracranial aneurysms. A systematic literature search up to January 1, 2013 was performed in PubMed. Two independent reviewers selected 8 studies that compared subtraction CTA with digital subtraction angiography. Data from the studies were used to construct a 2×2 contingency table on a per-patient basis in ≥5 diseased and 5 non-diseased patients, with additional data on a per-aneurysm basis. Overall, subtraction CTA had a pooled sensitivity of 99% [95% confidence interval (CI), 95-100%] and specificity of 94% (95% CI, 86-97%) for detecting and ruling out cerebral aneurysms, respectively, on a per-patient basis. On a per-aneurysm basis, the pooled sensitivity was 96% (95% CI, 90-99%), and the specificity was 91% (95% CI, 85-95%). In conclusion, subtraction CTA is a highly sensitive, specific and non-invasive method for the diagnosis and evaluation of intracranial aneurysms.

Diagnostic Impact of Bone-Subtraction CT Angiography for Patients with Acute Subarachnoid Hemorrhage.

Detection and evaluation of ruptured aneurysms is critical for choosing an appropriate endovascular or neurosurgical intervention. Our aim was to assess whether bone-subtraction CTA is capable of guiding treatment for cerebral aneurysms in patients with acute SAH and could replace DSA. We prospectively studied 116 consecutive patients with SAH with 16-detector row bone-subtraction CTA and DSA before intracranial aneurysm treatment. Two independent neuroradiologists reviewed the bone-subtraction CTA blinded to DSA (reference standard). We determined the accuracy of bone-subtraction CTA for aneurysm detection and the measurement of aneurysm dimensions and compared the radiation doses of the 2 imaging modalities. Seventy-one patients (61%) had 74 aneurysms on DSA. Bone-subtraction CTA detected 73 of these aneurysms, but it detected 1 additional aneurysm. On a per-aneurysm basis, sensitivity, specificity, and positive and negative predictive values for bone-subtraction CTA were 99%, 98%, and 99% and 98%, respectively. For aneurysms of ≤3 mm, sensitivity was 94% (95% CI, 73%-99%). Bone-subtraction CTA slightly overestimated neck and dome diameters by <0.2 mm and overestimated the dome-to-neck ratios by 2% on average. Dose-length product was 565 ± 201 mGy × cm for bone-subtraction CTA and 1609 ± 1300 mGy × cm for DSA. Bone-subtraction CTA is as accurate as DSA in detecting cerebral aneurysms after SAH, provides similar information about aneurysm configuration and measures, and reduces the average effective radiation dose for vascular diagnostics by 65%. Diagnostic equivalence in association with dose reduction suggests replacing DSA with bone-subtraction CTA in the diagnostic work-up of spontaneous SAH.

64-section multidetector CT angiography for evaluation of intracranial aneurysms: comparison with 3D rotational angiography

To assess the diagnostic performance of 64-section computed tomography angiography (CTA) for detection of cerebral aneurysms by comparison with the new gold standard three-dimensional (3D) digital subtraction angiography (DSA). A total of 128 patients who underwent both 64-section CTA and 3D DSA for suspected intracranial aneurysms were included. The location, size, and shape of the aneurysm were assessed and compared with 3D DSA results. The sensitivity, specificity, positive and negative predictive values of 64-section CTA were calculated by using 3D DSA as reference standard. According to the reference standard, a total of 145 aneurysms were detected at 3D DSA in 118 patients. Of these 145 aneurysms, 64-section CTA detected 139 aneurysms in 118 patients. The sensitivity of CTA for detection of aneurysm was 95.8% on a per-aneurysm basis. All missed aneurysms were non-causative very small aneurysms in patients harboring multiple aneurysms. On a per-patient basis, the sensitivity, specificity, positive and negative predictive values were 100%. Compared with the new gold standard 3D DSA, 64-section CTA offers high sensitivity and specificity for detection of intracranial aneurysms. It could be readily used as a screening imaging method for detection of intracranial aneurysms.

Cerebral Aneurysms: Accuracy of 320–Detector Row Nonsubtracted and Subtracted Volumetric CT Angiography for Diagnosis

To assess the accuracy of 320-detector row nonsubtracted and subtracted volumetric computed tomographic (CT) angiography for detection of cerebral aneurysms. After institutional review board approval and informed written consent were obtained, 282 consecutive patients suspected of having cerebral aneurysms underwent CT angiography with a 320-detector row volumetric CT scanner and three-dimensional (3D) rotational digital subtraction angiography (DSA). The sensitivity, specificity, and accuracy of nonsubtracted and subtracted volumetric CT angiography for depiction of aneurysms were analyzed, with 3D DSA as the reference standard. P values less than .05 were considered to indicate a significant difference. Among the 282 patients, 198 (70.2%) had 239 cerebral aneurysms that were detected on the basis of 3D DSA. Nonsubtracted volumetric CT angiography showed 231 of the 239 (96.7%) aneurysms. The primary reason for missed aneurysms was close proximity to bone tissue. Sensitivity, specificity, and accuracy of nonsubtracted volumetric CT angiography for depicting aneurysms were 96.7%, 100%, and 97.5%, respectively, on a per-aneurysm basis. Subtracted volumetric CT angiography showed 237 of 239 (99.2%) aneurysms. Sensitivity, specificity, and accuracy of subtracted volumetric CT angiography for depicting aneurysms were 99.2%, 100%, and 99.4%, respectively, on a per-aneurysm basis. There was no statistically significant difference in accuracy between subtracted volumetric CT angiography and 3D DSA (P = .500). However, nonsubtracted volumetric CT angiography was significantly less sensitive than 3D DSA and subtracted volumetric CT angiography (P = .031 and .008, respectively). Subtracted 320-detector row volumetric CT angiography provides excellent sensitivity for detection of cerebral aneurysms and should be the first-line imaging technique for the noninvasive evaluation of aneurysms. The accuracy of nonsubtracted volumetric CT angiography was lower than that for subtracted volumetric CT angiography, especially for aneurysms adjacent to bone tissue.

Cerebral Aneurysms: Accuracy of 320–Detector Row Nonsubtracted and Subtracted Volumetric CT Angiography for Diagnosis

Purpose To assess the accuracy of 320–detector row nonsubtracted and subtracted volumetric computed tomographic (CT) angiography for detection of cerebral aneurysms. Materials and Methods After institutional review board approval and informed written consent were obtained, 282 consecutive patients suspected of having cerebral aneurysms underwent CT angiography with a 320–detector row volumetric CT scanner and three-dimensional (3D) rotational digital subtraction angiography (DSA). The sensitivity, specificity, and accuracy of nonsubtracted and subtracted volumetric CT angiography for depiction of aneurysms were analyzed, with 3D DSA as the reference standard. P values less than .05 were considered to indicate a significant difference. Results Among the 282 patients, 198 (70.2%) had 239 cerebral aneurysms that were detected on the basis of 3D DSA. Nonsubtracted volumetric CT angiography showed 231 of the 239 (96.7%) aneurysms. The primary reason for missed aneurysms was close proximity to bone tissue. Sensitivity, specificity, and accuracy of nonsubtracted volumetric CT angiography for depicting aneurysms were 96.7%, 100%, and 97.5%, respectively, on a per-aneurysm basis. Subtracted volumetric CT angiography showed 237 of 239 (99.2%) aneurysms. Sensitivity, specificity, and accuracy of subtracted volumetric CT angiography for depicting aneurysms were 99.2%, 100%, and 99.4%, respectively, on a per-aneurysm basis. There was no statistically significant difference in accuracy between subtracted volumetric CT angiography and 3D DSA (P = .500). However, nonsubtracted volumetric CT angiography was significantly less sensitive than 3D DSA and subtracted volumetric CT angiography (P = .031 and .008, respectively). Conclusion Subtracted 320–detector row volumetric CT angiography provides excellent sensitivity for detection of cerebral aneurysms and should be the first-line imaging technique for the noninvasive evaluation of aneurysms. The accuracy of nonsubtracted volumetric CT angiography was lower than that for subtracted volumetric CT angiography, especially for aneurysms adjacent to bone tissue. ©RSNA, 2013 An earlier incorrect version of this article appeared online. This article was corrected on July 22, 2016.

Diagnosing residual or recurrent cerebral aneurysms after clipping by computed tomographic angiography: Meta-analysis

A cerebral aneurysm with incomplete treatment may re-grow and cause new bleeding. This meta-analysis calculates the sensitivity and specificity of computed tomographic angiography (CTA) in the detection of the residual or recurrent cerebral aneurysms after clipping, in comparison with digital subtraction angiography (DSA). Between October 1997 and October 2012, relevant data were systematically and prospectively collected without language restrictions from the PUBMED and EMBASE databases for analysis. A total of 10 eligible studies compared CTA with DSA in the detection of the residual or recurrent cerebral aneurysms after clipping by two independent observers. The sensitivity, specificity, positive likelihood ratio (+LR), and negative likelihood ratio (-LR) were calculated on a per-aneurysm basis, and the area under the sROC curve (AUC), heterogeneity, and publication bias also were evaluated. A total of 487 aneurysms were included for meta-analysis. The pooled sensitivity, specificity, +LR, -LR, DOR, and AUC of CTA for detecting the residual or recurrent aneurysms after clipping were 71%, 94%, 9.39, 0.32, 28.32, and 0.8558, respectively. The between-study heterogeneity of DOR and the presence of publication bias were not statistically significant. As a noninvasive and convenient screening method, CTA has a high diagnostic value for the detection of the residual or recurrent aneurysms after clipping. In the future, it may be used as a routine diagnostic tool for evaluation of aneurysms after clipping.

O-026 Coil costs and aneurysm size: 2 years of data

The material costs associated with endovascular treatment of cerebral aneurysms include access catheters, equipment utilization, personnel costs, and embolization materials. The costs of coiling aneurysms in general has been discussed,...

Digital Subtraction CT Angiography for Detection of Intracranial Aneurysms: Comparison with Three-dimensional Digital Subtraction Angiography

To evaluate the diagnostic accuracy of digital subtraction computed tomographic (CT) angiography in the detection of intracranial aneurysms compared with three-dimensional (3D) rotational digital subtraction angiography (DSA), as reference standard, in a large cohort in a single center. The study was waived by the institutional review board because of its retrospective nature. A total of 513 patients clinically suspected of having or with known intracranial aneurysms and other cerebral vascular diseases underwent both digital subtraction CT angiography with a dual-source CT scanner and 3D DSA, with a median interval of 1 day; 436 patients (84.9%) had acute subarachnoid hemorrhage at presentation. The sensitivity, specificity, and accuracy of digital subtraction CT angiography in depicting aneurysm were analyzed on a per-patient and per-aneurysm basis, with 3D DSA as the reference standard. The sensitivity, specificity, and accuracy of digital subtraction CT angiography in depicting aneurysms of different diameter (ie, <3 mm, 3-5 mm, 5-10 mm, and >10 mm) and of aneurysms at different locations in the anterior and posterior circulation were calculated. Kappa statistics were calculated to quantify inter- and intrareader variability in detecting aneurysms by using digital subtraction CT angiography for 100 patients. Of 513 patients, 106 (20.7%) had no aneurysms, while 407 patients (79.3%) had 459 aneurysms at 3D DSA. Digital subtraction CT angiography correctly depicted 456 (99.3%) of the 459 aneurysms. By using 3D DSA as the standard of reference, the sensitivity and specificity of depicting intracranial aneurysms were 97.8% (398 of 407) and 88.7% (94 of 106), respectively, on a per-patient basis, and 96.5% (443 of 459) and 87.8% (94 of 107), respectively, on a per-aneurysm basis. Digital subtraction CT angiography had sensitivities of 91.3% (42 of 46), 94.0% (140 of 149), 98.4% (186 of 189), and 100% (75 of 75) in depicting aneurysms of less than 3 mm, between 3 mm but less than 5 mm, between 5 mm but less than 10 mm, and 10 mm or greater, respectively, and of 95.8% (276 of 288) and 97.7% (167 of 171) in depicting anterior circulation and posterior circulation aneurysms, respectively. Excellent inter- and intrareader agreement was found on a per-patient (κ=0.900 and 0.939, both P<.001) and per-aneurysm basis (κ=0.846 and 0.921, both P<.001) for the detection of intracranial aneurysms with digital subtraction CT angiography. Digital subtraction CT angiography has a high sensitivity and specificity in depicting intracranial aneurysms with different sizes and at different locations, compared with 3D DSA.

Comparison of the accuracy of subtraction CT angiography performed on 320-detector row volume CT with conventional CT angiography for diagnosis of intracranial aneurysms

The accuracy of diagnosis of intracranial aneurysms by subtraction computed tomography angiography (CTA) was compared with conventional non-subtracted CTA and with digital subtraction angiography (DSA). 56 patients with spontaneous subarachnoid hemorrhage (SAH) and suspected intracranial aneurysms were evaluated from September 2009 to January 2010. All underwent 320-detector row volume CT-CTA examinations. Non-contrast CT of each patient's head with the same scan range was performed before the routine CTA scan as the mask image for subtraction. The subtraction CTA volume data was obtained by subtracting the mask image volume data from the conventional non-subtracted CTA volume data. Subtraction and conventional CTA volume data were transmitted to a VOXAR workstation and two physicians with experience in diagnostic imaging of the nervous system independently carried out image post-processing and judged the results. Neurosurgeons performed endovascular treatment or surgical clipping based on information available through the CTA alone. In 42 patients, 51 aneurysms were detected by DSA. On a per-aneurysm basis, the diagnostic sensitivity of subtraction CTA was 98.9% for physician 1 and 100% for physician 2. The sensitivity of conventional CTA was 93.7% for physician 1 and 92.6% for physician 2. There was excellent inter-observer agreement (κ=0.84, 95% confidence interval 0.82-0.85). The overall sensitivity, specificity, positive predictive and negative predictive values of subtraction CTA were all 100%. The overall sensitivity, specificity, positive predictive and negative predictive values of non-subtracted CTA were 94%, 100%, 100% and 76%, respectively. Therapeutic decisions could be made for all 42 patients based on subtraction CTA images, whereas conventional non-subtracted CTA provided sufficient information to make therapeutic decisions for only 35 patients. Conventional CTA has lower sensitivity for the detection of very small aneurysms and aneurysms adjacent to the skull when compared to subtraction CTA. Subtraction CTA performed on a 320-detector row volume CT is an accurate diagnostic tool that provides data equivalent to that obtained with three-dimensional-DSA for the detection of intracranial aneurysms.

Diagnosing cerebral aneurysms by computed tomographic angiography: Meta‐analysis

Cerebral aneurysms can cause substantial morbidity and mortality, specifically if they rupture, leading to nontraumatic subarachnoid hemorrhage (SAH). This meta-analysis summarizes evidence about the accuracy of noninvasive computed tomographic (CT) angiography for diagnosing intracranial aneurysms in symptomatic patients. Four databases including PubMed were searched without language restrictions from January 1995 to February 2010. Two independent reviewers selected and extracted 45 studies that compared CT angiography with digital subtraction angiography (DSA) and/or intraoperative findings in patients suspected of having cerebral aneurysms. Data from eligible studies were used to reconstruct 2 x 2 contingency tables on a per-patient basis in at least 5 diseased and 5 nondiseased patients, with additional data on a per-aneurysm basis when available. The 45 included studies generally were of high methodological quality. Among the 3,643 patients included, about 86% had nontraumatic SAH, and 77% had cerebral aneurysms. Overall, CT angiography had a pooled sensitivity of 97.2% (95% confidence interval, 95.8-98.2%) for detecting and specificity of 97.9% (95.7-99.0%) for ruling out cerebral aneurysms on a per-patient basis. On a per-aneurysm basis, the pooled sensitivity was 95.0% (93.2-96.4%), and the specificity 96.2% (92.9-98.0%). The diagnostic accuracy of CT angiography with 16- or 64-row multidetector CT was significantly higher than that of single-detector CT, especially in detecting small aneurysms of ≤ 4 mm in diameter. CT angiography has a high accuracy in diagnosing cerebral aneurysms, specifically when using modern multidetector CT. In the future, CT angiography may increasingly supplement or selectively replace DSA in patients suspected of having a cerebral aneurysm.

Evaluation of intracranial aneurysms using dual-source computed tomographic angiography and digital subtraction angiography

To compare the values of dual-source computed tomographic angiography (DSCTA) and digital subtraction angiography (DSA) in evaluating intracranial aneurysms in patients with nontraumatic subarachnoid hemorrhages (SAH) . Totally 80 nontraumatic SAH patients were evaluated with both DSCTA and DSA. With the results of DSA as the gold standards, the sensitivity, specificity, and accuracy of DSCTA was calculated, and the agreement between these two modes was analyzed. A total of 73 aneurysms were detected by DSCTA in 65 patients, 74 aneurysms were detected by DSA in 63 patients. 2 cases were false positive and 3 aneurysms were missed by DSCTA. The sensitivity, specificity and accuracy of DSCTA were 95.5%, 88.2%, and 94% on a per-patient basis and were 95.9%, 88.2%, and 94.5% on a per-aneurysm basis. For patients with nontraumatic SAH, DSCTA and DSA have comparable abilities in detecting and displaying aneurysms.

Automatic Bone Removal Dual-Energy CT Angiography for the Evaluation of Intracranial Aneurysms

To evaluate the diagnostic accuracy of dual-energy computed tomographic angiography (DE-CTA) in the detection of intracranial aneurysms and to determine whether DE-CTA provides adequate information to guide treatment choice. Eighty patients (31 men and 49 women; mean [SD] ages of 52 [9] years) with spontaneous subarachnoid hemorrhage underwent DE-CTA. The performance of DE-CTA was compared with conventional CTA created from average weighted images and digital subtraction angiography (DSA). Sensitivity and specificity for aneurysm detection were determined on a per-patient and per-aneurysm basis. The treatment choice was assessed on the basis of aneurysm neck size and/or the dome/neck ratio. With DSA as reference standard (n = 61; 47 aneurysms in 41 patients), DE-CTA correctly detected 45 aneurysms in 41 patients corresponding to sensitivity and specificity of 100% and 95.0% on a per-patient basis versus 95.7% and 95.0% on a per-aneurysm basis, whereas conventional CTA correctly detected 43 aneurysms in 39 patients corresponding to sensitivity and specificity of 95.1% and 95.0% on a per-patient basis versus 91.5% and 95.0% on a per-aneurysm basis. No statistical difference between DE-CTA and conventional CTA was found for the diagnostic evaluation of intracranial aneurysms. Surgery was performed to treat 38 aneurysms, coiling in 26 aneurysms, stent in one patient, and follow-up in the remaining 5 aneurysms. Dual-energy CTA correctly predicted treatment choice in 44 aneurysms, with 15 aneurysms coiled and 29 aneurysms clipped. Compared with DSA, DE-CTA had a comparable diagnostic accuracy for the detection of intracranial aneurysms, visualization of the morphology of aneurysms at the skull base, and prediction of aneurysm treatment choice in most patients with spontaneous subarachnoid hemorrhage based on this study.

Comparison of 16-row multislice CT angiography with conventional angiography for detection and evaluation of intracranial aneurysms

The aim of this study is to compare the diagnostic performance of 16-row computed tomographic angiography (MDCTA) with digital subtraction angiography (DSA) for the detection and characterization of intracranial aneurysms in patients with nontraumatic subarachnoid hemorrhages (SAH). One-hundred and twelve consecutive patients with suspected intracranial aneurysm underwent both 16-row MDCTA and DSA. The MDCT angiograms were interpreted in a blinded fashion by using combination with VRI, MIP and MPR techniques. Sensitivity specificity and accuracy were calculated for the CTA and DSA. The results were compared with each other. The DSA reader's interpretation was accepted as the reference standard. A total of 164 aneurysms were detected at DSA in 112 patients, no aneurysms were detected by DSA and MDCTA in 16 patients. Eight aneurysms were missed by MDCTA. The overall sensitivity, specificity, and accuracy of MDCTA on a per-aneurysm basis were 95.1%, 94.1%, and 95%, respectively. According to the size of the aneurysm less than 3mm; sensitivity, specificity and diagnostic accuracy of MDCTA were 86.1%, 94.1%, 88.6%, respectively. This study suggests that MDCTA is equally as sensitive as DSA in the detection of intracranial aneurysms of greater than 3mm, and it also reveals 100% detection rate for ruptured aneurysms.

Application of multislice computed tomographic angiography in diagnosis and treatment of intracranial aneurysms

Objectives The aim of the study is to assess the clinical value of 16-row multislice computed tomographic angiography (CTA) for detection and treatment of intracranial aneurysms. Patients and methods Between January 2005 and October 2008, 388 patients were included and successively underwent 16-slice CTA for suspected intracranial aneurysms. Three neuroradiologists independently reviewed CTA and DSA images. The combined interpretations of digital subtraction angiography (DSA) and surgical findings were considered as the ultimate reference standard against which the diagnostic accuracy of CTA and DSA were compared. Results The reference standard revealed 287 aneurysms in 256 patients. There was no statistically significant difference in accuracy between 16-slice CTA and conventional DSA. The sensitivity, specificity, and accuracy of 16-slice CTA in detecting all aneurysms were 98.3, 97.0, and 97.9%, respectively, on a per-aneurysm basis. The sensitivity of 16-slice CTA was 90.0% for reader 1 and 93.3% for reader 2 for less than 3 mm aneurysms. One hundred eighty-nine aneurysms were deemed amenable to endovascular therapy on the basis of CTA images, 98% of whom (185) were successfully treated with this method. Forty-eight aneurysms were considered candidates for surgical treatment, and all aneurysms were deemed completely occluded during surgical clipping. Sixteen-slice CTA images provided important preoperative information, which could assist the endovascular and surgical therapy of aneurysms. Conclusions Sixteen-slice CTA is a highly accurate imaging examination of the first line imaging technique for the detection of intracranial aneurysms, and it can provide sufficient diagnostic information in guiding the surgical and endovascular therapy of aneurysms.